Assessment of Gas Generation in Underground Repository of Low-Level Waste

In a repository containing low-level waste, gas generation will occur principally by the coupled processes of metal corrosion and microbial degradation of cellulosic waste. This paper describes a mathematical model designed to address gas generation by these mechanisms and assesses the potential effects of gas generation on the performance of a radioactive waste repository. The metal corrosion model incorporates a three-stage process encompassing aerobic and anaerobic corrosion regimes; the microbial degradation model simulates the activities of eight different microbial populations, which are maintained as functions both of pH and of the concentrations of particular chemical species. A prediction is made for gas concentrations and generation rated over an assessment period of ten thousand years in a radioactive waste repository. The results suggest that H2 will be the principal gas generated within the radioactive waste cavern. 10 figs., 6 tabs., 12 refs. (Author) 15 figs.,